Method of forming membrane electrode assemblies for electrochemical devices

Abstract

A method of forming a membrane electrode assembly (MEA) includes first bonding a first electrode layer to a first side of an ion-exchange membrane. The method may further include protecting a second side of the membrane with a release sheet. The method may further include removing the release sheet and bonding the second side of the membrane to a first side of a second electrode layer. The method may further include positioning venting members on a second side of the second electrode layer to remove at least one of a liquid and a vapor that may be generated during the bonding process. In another embodiment an electrocatalyst can first bond to at least one side of the membrane, and subsequently, to a gas diffusion layer. An opposing side of the membrane can bond to an electrode layer in aqueous state.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit under 35 U.S.C.§119(e) of U.S. Provisional Patent Application Ser. No. 60 / 872,428 filed Jan. 31, 2006 (formerly U.S. application Ser. No. 11 / 343,746, converted to provisional by petition filed Jan. 17, 2007), which application is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention is generally directed toward improved methods for making gas diffusion electrodes for electrochemical devices, and more particularly, to methods of achieving a smoother surface of the gas diffusion electrodes at an ion-exchange membrane interface.[0004]2. Description of the Related Art[0005]Electrochemical cells comprising ion exchange membranes, such as proton exchange membranes (PEMs), for example, polymer electrolyte membranes may be operated as fuel cells, wherein a fuel and an oxidant are electrochemically converted at the cell electrodes to...

AI Technical Summary

Benefits of technology

This method effectively reduces surface roughness, enhances bonding between the membrane and electrodes, minimizes cracks, and improves fluid diffusion, reducing fuel waste and corrosion, while being less time-consuming and cost-effective compared to existing methods.

Problems solved by technology

Although the above-described methods have introduced limited reduction of surface roughness of the electrode layers 1, 3 at the ion-exchange membrane 2 interface, obstacles persist.

For example, surface roughness continues to present difficulties in bonding the membrane 2 to the electrode layers 1, 3.

Additionally, cracks, similar to those in FIGS. 6-9, continue to emerge, resulting in inefficient fluid diffusion, fuel waste, mass transport losses and corrosion of the MEA 5 components.

Furthermore, processes such as hot compaction are expensive and time-consuming.

Other methods such as Teflon-based electrocatalysts for electrode layers 1, 3, such as cathodes, have resulted in mass transport losses.

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